Element recovery method and element recovery apparatus

Patent metadata

Field	Value
Publication number	US-10309022-B2
Application number	US-201214236949-A
Country	US
Kind code	B2
Filing date	Aug 8, 2012
Priority date	Aug 10, 2011
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

An element recovery method and an element recovery apparatus are provided by which an element containing a high-purity rare earth element can be recovered at low cost. The element recovery method includes the steps of: preparing molten salt containing a rare earth element; and controlling electric potentials in a pair of electrode members at prescribed values while keeping the pair of electrode members in contact with the molten salt, thereby depositing the rare earth element existing in the molten salt on one of the pair of electrode members. In this way, as compared with the conventional wet separation method, an element such as a rare earth element that is to be recovered can be directly recovered from the molten salt in which the element is dissolved, so that the steps of the recovery method can be simplified and reduced in cost.

First claim

The invention claimed is:

1. An element recovery method comprising:
placing an object to be processed and an electrode member in contact with molten salt, the object to be processed being conductive and containing at least two rare earth elements, wherein the object to be processed is previously pulverized and is held in a basket, the basket being a member configured to wrap the object to be processed, and wherein one of the at least two of the rare earth elements has a first deposition potential and the other of the at least two of the rare earth elements has a second deposition potential, and the first deposition potential is higher than the second deposition potential;
eluting the at least two of the rare earth elements from the object to be processed held in the basket into the molten salt by controlling electric potentials in the object to be processed and the electrode member while keeping the object to be processed and the electrode member in contact with the molten salt,
after the at least two of the rare earth elements are eluted from the object to be processed, depositing one of the rare earth elements on the electrode member by controlling an electrical potential of the electrode member so as to set the electrical potential of the electrode member at a first value lower than the first deposition potential and higher than the second deposition potential; and
after the electrical potential of the electrode member is set at the first value, setting the electrical potential of the electrode member at a second value lower than the second deposition potential,
wherein the deposition potentials for the at least two rare earth elements are different for each of the at least two rare earth elements and depend on the composition and temperature of the molten salt, and
wherein during the controlling of the electric potentials in the object to be processed and the electrode member, the electric potentials in the object to be processed and the electrode member in contact with the molten salt are changed.

2. The element recovery method according to claim 1 , wherein the object to be processed contains a d-block transition metal.

3. The element recovery method according to claim 1 , wherein one of chloride-based molten salt and fluoride-based molten salt is used as the molten salt.

4. The element recovery method according to claim 1 , wherein the molten salt is a combined molten salt of chloride-based molten salt and fluoride-based molten salt.

5. The element recovery method according to claim 1 , wherein the electrode member includes two or more electrodes.

6. The element recovery method according to claim 5 , further comprising:
setting the electric potential of one of the electrodes at the first value; and
setting the electrical potential of the other of the electrodes at the second value.

7. The element recovery method according to claim 1 , wherein the electrode member is a plate.

Assignees

• Awazu Tomoyuki
• Sugihara Takayasu
• Majima Masatoshi
• Nohira Toshiyuki
• Hagiwara Rika
• Kobayashi Seitaro
• Sumitomo Electric Industries
• Univ Kyoto

Inventors

• Awazu Tomoyuki
• Sugihara Takayasu
• Majima Masatoshi
• Nohira Toshiyuki
• Hagiwara Rika
• Kobayashi Seitaro

Classifications

• C25C7/002

  of cells comprising at least an electrode made of particles (C25C7/005, C25C7/02 - C25C7/06 take precedence) · CPC title

• C25C3/34 Primary

  of metals not provided for in groups C25C3/02 - C25C3/32 · CPC title

• C22B59/00

  Obtaining rare earth metals · CPC title